This application claims the benefit of Korean Application No. 2002-29952, filed May 29, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a developing apparatus of a dry electrophotographic image forming apparatus, and more particularly, to a developing apparatus having a sealing member to prevent leakage of dry toner (hereinafter referred to as toner) contained in the developing apparatus.
2. Description of the Related Art
In general, a dry electrophotographic image forming apparatus contains toner and supplies the toner to a photoreceptor medium, such as a photoreceptor drum or the like, to develop a latent electrostatic image on the photoreceptor medium. Here, the toner is minute powder having a predetermined color and has to be contained in the developing apparatus except when being adhered to the latent electrostatic image. Therefore, the developing apparatus of the dry electrophotographic image forming apparatus using toner generally has a sealing member to prevent leakage of the toner.
FIG. 1 is an exploded perspective view of a conventional developing apparatus having sealing members. As shown in FIG. 1, the conventional developing apparatus includes a housing 100 which contains toner, and a blade 130 and a developer roller 120 which are respectively combined with the housing 100. The conventional developing apparatus also includes sealing members 140 which are disposed on insides 102 of right and left walls 104 of the housing 100 and closely contact the blade 130 and the developer roller 120 to prevent the toner in the housing 100 from leaking.
The developer roller 120 is coupled to couplings 101 which are prepared in the right and left walls 104 of the housing 100, to rotate. The developer roller adheres the toner in the housing 100 onto an outer circumference thereof, and supplies the toner to a photoreceptor drum (not shown) to develop a latent electrostatic image on the photoreceptor drum.
The blade 130 is conjoined with an upper surface 103 of the housing 100 in order to longitudinally contact the outer circumference of the developer roller 120. Thus, the blade 130 rubs against the outer circumference of the developer roller 120 that is rotating to scrape away the toner excessively adhered onto the outer circumference of the developer roller 120 so as to form a toner layer having a predetermined thickness.
Here, a length L2 of the developer roller 120 is smaller than an inner distance L1 between the right and left walls 104 of the housing 100, and a length L3 of the bladed 130 is smaller than the length L2 of the developer roller 120. Thus, the toner may leak through gaps between right and left ends 121 of the developer roller 120 and the insides 102 of the right and left walls 104 of the housing 100, and gaps between the blade 130 and the insides 102 of the right and left walls 104 of the housing 100. Therefore, in order to prevent leakage of the toner, the sealing members 140 are disposed on the insides 102 of the right and left walls 104 of the housing 100.
Since the sealing members 140 are generally formed of a sponge material, the sealing members 140 elastically and closely contact the outer circumference of the developer roller 120, the blade 130, and the insides 102 of the right and left walls 104 of the housing 100.
According to the above-described structure, when the sealing members 140, the blade 130, and the developer roller 120 are sequentially combined with the housing 100, the sealing members 140 closely contact the insides 102 of the right and left walls 104 of the housing 100, the outer circumference of the developer roller 120, and the blade 130. Thus, gaps between the right and left ends 121 of the developer roller 120 and the insides 102 of the right and left walls 104 of the housing 100, and gaps between the blade 130 and the insides 102 of the right and left walls 104 of the housing 100 are blocked to prevent leakage of the toner.
As described above, the length L2 of the developer roller 120 is smaller than the inner distance L1 between the right and left walls 104 of the housing 100, and the length L3 of the blade 130 is smaller than the length L2 of the developer roller 120. Thus, a contact width T2 between the blade 130 and the sealing member 140 is smaller than a width T1 of the sealing member 140.
FIG. 2A is a partial perspective view of the assembled conventional developing apparatus of FIG. 1, and FIG. 2 is an enlarged view of portion C of FIG. 2A. FIG. 3A is a cross-sectional view along cutting plane line A-Axe2x80x2 of FIG. 2A, and FIG. 3B is an enlarged view of portion D of FIG. 3A.
As shown in FIGS. 2A, 2B, 3A, and 3B, lower portions of a front part 141 (shown in FIG. 1) of the sealing members 140 closely contact the outer circumference of the developer roller 120, and upper portions of the front part 141 of the sealing members 140 closely contact an inside surface 131 (shown in FIG. 1) of the blade 130 by the contact width T2.
A lower long side part 133 of the blade 130 has a bent portion 134, perpendicular to the long side part 133, in order to prevent the outer circumference of the developer roller 120 from being damaged due to contact with the blade 130. Since the bent portion 134 raises the sealing member 140, the sealing member 140 does not contact the outer circumference of the developer roller 120 at a portion in which the bent portion 134 is formed, thereby forming a gap 160. Reference character xe2x80x9caxe2x80x9d of FIG. 2B represents a portion of the sealing member 140 which does not contact the blade 130, but is pulled and deformed in a direction 145 due to a portion of the sealing member 140 that contacts the blade 130 to be compressed, thereby forming a gap 150 between the sealing member 140 and the outer circumference of the developer roller 120. As a result of the above, the toner in the housing 100 may leak through gaps 160 and 150.
Accordingly, it is an aspect of the present invention to provide a developing apparatus having a sealing member which prevents deterioration of the sealing member due to compression and deformation of the sealing member.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and/or other aspects of the present invention are achieved by providing a developing apparatus including a housing, a developer roller, a blade, and sealing members. The housing contains toner. The developer roller is combined with the housing to rotate and adheres the toner onto an outer circumference thereof to supply the toner out of the housing. The blade controls an amount of toner that is adhered onto the outer circumference of the developer roller. The sealing members are installed on both inside walls of the housing and closely contact the housing, the developer roller, and the blade to prevent the toner from leaking out. The sealing members include a first sealing member and a second sealing member. The first sealing member has a side part that elastically and closely contacts the inside walls of the housing and a short side part of the blade, and a front part that elastically and closely contacts the outer circumference of the developer roller. The second sealing member overlaps with the first sealing member and has a front part that elastically and closely contacts an inside surface of the blade and the outer circumference of the developer roller.
According to an aspect of the invention, the second sealing member further includes a horizontal slit which is cut along a contact line with a lower long side part of the blade. The horizontal slit is cut at least to a depth in which the second sealing member is compressed when the blade is combined with the housing. The second sealing member overlaps with and is attached to the first sealing member.
According to an aspect of the invention, the developing apparatus includes the sealing member having a side part, a front part, and a vertical slit. The side part closely contacts the inside walls of the housing. The front part has an upper portion that partially overlaps with and elastically and closely contacts an inside surface of the blade, and a lower portion that elastically and closely contacts the outer circumference of the developer roller. The vertical slit is cut along a short side part of the blade at least up to a lower long side part of the blade.
According to an aspect of the invention, the sealing member further includes a horizontal slit which is cut along a contact line with the lower long side part of the blade to the short side part of the blade.
According to an aspect of the invention, the vertical slit is cut at least to a depth in which the sealing member is compressed when the blade is combined with the housing.
According to another aspect of the invention, the horizontal slit is cut at least to a depth in which the sealing member is compressed when the blade is combined with the housing.